Constructing a PVDF-based composite solid-state electrolyte with high ionic conductivity Li6.5La3Zr1.5Ta0.1Nb0.4O12 for lithium metal battery

Abstract

A high-safety composite solid-state electrolyte (CSSE) was constructed by embedding the high ionic conductivity garnet type Li6.5La3Zr1.5Ta0.1Nb0.4O12 (LLZTNO) powder into a polyvinylidene fluoride (PVDF) matrix. The ionic conductivity of the CSSE containing 10% LLZTNO could reach 1.05 × 10−4 S cm−1, and the electrochemical window was extended to 4.80 V vs Li/Li+. In addition, the evolution and composition of the SEI layer were characterized by in-situ optical microscopic observation, X-ray photoelectron spectroscopy and cryogenic electron microscopy (cryo-EM). When paired with an NCM811 cathode, the batteries showed good rate cycling performance, and the discharge capacity could be maintained at 137.1 and 91.2 mAh g−1 at 0.3C and 2C after 80 and 100 cycles. The needle penetration test further demonstrated superior safety and potential applications of the PVDF-based room-temperature CSSE batteries.